1. Field of the Invention
The invention is directed to a vibration damper with at least two tube elements arranged one inside the other and a piston rod that is movable in a piston rod guide, wherein a valve comprising a valve slide for at least partially closing at least one flow path of a fluid flowing through the valve is arranged in the region of the one end of the piston rod guide, and the valve has an input side and an output side.
2. Description of the Prior Art
It is known to use valves in vibration dampers. In twin-tube vibration dampers, there is usually a base valve at the bottom of the working cylinder. Further, the piston can have a piston valve. In this case, the valves are compression valves.
It is further known, e.g., from DE 34 34 877 A1, to provide twin-tube dampers with an adjustable damping force in that a damping force generating device outside of the twin-tube damper is fluidically connected to the interior of the twin-tube damper. The resistance to the fluid can be adjusted at this damping valve to control the damping force of the vibration damper.
In order to produce damping valves of this type more economically it is necessary to limit the volume flow through the damping valve. Of course, flow valves for influencing the flow of a fluid are already known. In particular, there are two-way flow control valves, three-way flow control valves, or flow-dividing valves. But known flow valves cannot be utilized for the specified application in a vibration damper because they are either electrically operated or, by reason of their manner of operation, cannot be controlled purely as a function of volume flow.
In a vibration damper with adjustable damping force known from DE 102004054474 B3, there is arranged upstream of an adjustable damping valve an additional damping valve. In this way, maximum pressures that occur suddenly, for example when driving over a bump, can be contained and kept away from the adjustable damping valve.